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Dulin D. An Introduction to Magnetic Tweezers. Methods Mol Biol 2024; 2694:375-401. [PMID: 37824014 DOI: 10.1007/978-1-0716-3377-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Magnetic tweezers are a single-molecule force and torque spectroscopy technique that enable the mechanical interrogation in vitro of biomolecules, such as nucleic acids and proteins. They use a magnetic field originating from either permanent magnets or electromagnets to attract a magnetic particle, thus stretching the tethering biomolecule. They nicely complement other force spectroscopy techniques such as optical tweezers and atomic force microscopy (AFM) as they operate as a very stable force clamp, enabling long-duration experiments over a very broad range of forces spanning from 10 fN to 1 nN, with 1-10 milliseconds time and sub-nanometer spatial resolution. Their simplicity, robustness, and versatility have made magnetic tweezers a key technique within the field of single-molecule biophysics, being broadly applied to study the mechanical properties of, e.g., nucleic acids, genome processing molecular motors, protein folding, and nucleoprotein filaments. Furthermore, magnetic tweezers allow for high-throughput single-molecule measurements by tracking hundreds of biomolecules simultaneously both in real-time and at high spatiotemporal resolution. Magnetic tweezers naturally combine with surface-based fluorescence spectroscopy techniques, such as total internal reflection fluorescence microscopy, enabling correlative fluorescence and force/torque spectroscopy on biomolecules. This chapter presents an introduction to magnetic tweezers including a description of the hardware, the theory behind force calibration, its spatiotemporal resolution, combining it with other techniques, and a (non-exhaustive) overview of biological applications.
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Affiliation(s)
- David Dulin
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
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2
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Kolbin D, Walker BL, Hult C, Stanton JD, Adalsteinsson D, Forest MG, Bloom K. Polymer Modeling Reveals Interplay between Physical Properties of Chromosomal DNA and the Size and Distribution of Condensin-Based Chromatin Loops. Genes (Basel) 2023; 14:2193. [PMID: 38137015 PMCID: PMC10742461 DOI: 10.3390/genes14122193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/28/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
Transient DNA loops occur throughout the genome due to thermal fluctuations of DNA and the function of SMC complex proteins such as condensin and cohesin. Transient crosslinking within and between chromosomes and loop extrusion by SMCs have profound effects on high-order chromatin organization and exhibit specificity in cell type, cell cycle stage, and cellular environment. SMC complexes anchor one end to DNA with the other extending some distance and retracting to form a loop. How cells regulate loop sizes and how loops distribute along chromatin are emerging questions. To understand loop size regulation, we employed bead-spring polymer chain models of chromatin and the activity of an SMC complex on chromatin. Our study shows that (1) the stiffness of the chromatin polymer chain, (2) the tensile stiffness of chromatin crosslinking complexes such as condensin, and (3) the strength of the internal or external tethering of chromatin chains cooperatively dictate the loop size distribution and compaction volume of induced chromatin domains. When strong DNA tethers are invoked, loop size distributions are tuned by condensin stiffness. When DNA tethers are released, loop size distributions are tuned by chromatin stiffness. In this three-way interaction, the presence and strength of tethering unexpectedly dictates chromatin conformation within a topological domain.
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Affiliation(s)
- Daniel Kolbin
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (D.K.); (J.D.S.)
| | - Benjamin L. Walker
- Department of Mathematics, University of California-Irvine, Irvine, CA 92697, USA;
| | - Caitlin Hult
- Department of Mathematics, Gettysburg College, Gettysburg, PA 17325, USA
| | - John Donoghue Stanton
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (D.K.); (J.D.S.)
| | - David Adalsteinsson
- Department of Mathematics and Carolina Center for Interdisciplinary Applied Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (D.A.); (M.G.F.)
| | - M. Gregory Forest
- Department of Mathematics and Carolina Center for Interdisciplinary Applied Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (D.A.); (M.G.F.)
- Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (D.K.); (J.D.S.)
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3
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Bartas M, Slychko K, Červeň J, Pečinka P, Arndt-Jovin DJ, Jovin TM. Extensive Bioinformatics Analyses Reveal a Phylogenetically Conserved Winged Helix (WH) Domain (Zτ) of Topoisomerase IIα, Elucidating Its Very High Affinity for Left-Handed Z-DNA and Suggesting Novel Putative Functions. Int J Mol Sci 2023; 24:10740. [PMID: 37445918 DOI: 10.3390/ijms241310740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/13/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
The dynamic processes operating on genomic DNA, such as gene expression and cellular division, lead inexorably to topological challenges in the form of entanglements, catenanes, knots, "bubbles", R-loops, and other outcomes of supercoiling and helical disruption. The resolution of toxic topological stress is the function attributed to DNA topoisomerases. A prominent example is the negative supercoiling (nsc) trailing processive enzymes such as DNA and RNA polymerases. The multiple equilibrium states that nscDNA can adopt by redistribution of helical twist and writhe include the left-handed double-helical conformation known as Z-DNA. Thirty years ago, one of our labs isolated a protein from Drosophila cells and embryos with a 100-fold greater affinity for Z-DNA than for B-DNA, and identified it as topoisomerase II (gene Top2, orthologous to the human UniProt proteins TOP2A and TOP2B). GTP increased the affinity and selectivity for Z-DNA even further and also led to inhibition of the isomerase enzymatic activity. An allosteric mechanism was proposed, in which topoII acts as a Z-DNA-binding protein (ZBP) to stabilize given states of topological (sub)domains and associated multiprotein complexes. We have now explored this possibility by comprehensive bioinformatic analyses of the available protein sequences of topoII representing organisms covering the whole tree of life. Multiple alignment of these sequences revealed an extremely high level of evolutionary conservation, including a winged-helix protein segment, here denoted as Zτ, constituting the putative structural homolog of Zα, the canonical Z-DNA/Z-RNA binding domain previously identified in the interferon-inducible RNA Adenosine-to-Inosine-editing deaminase, ADAR1p150. In contrast to Zα, which is separate from the protein segment responsible for catalysis, Zτ encompasses the active site tyrosine of topoII; a GTP-binding site and a GxxG sequence motif are in close proximity. Quantitative Zτ-Zα similarity comparisons and molecular docking with interaction scoring further supported the "B-Z-topoII hypothesis" and has led to an expanded mechanism for topoII function incorporating the recognition of Z-DNA segments ("Z-flipons") as an inherent and essential element. We further propose that the two Zτ domains of the topoII homodimer exhibit a single-turnover "conformase" activity on given G(ate) B-DNA segments ("Z-flipins"), inducing their transition to the left-handed Z-conformation. Inasmuch as the topoII-Z-DNA complexes are isomerase inactive, we infer that they fulfill important structural roles in key processes such as mitosis. Topoisomerases are preeminent targets of anti-cancer drug discovery, and we anticipate that detailed elucidation of their structural-functional interactions with Z-DNA and GTP will facilitate the design of novel, more potent and selective anti-cancer chemotherapeutic agents.
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Affiliation(s)
- Martin Bartas
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Kristyna Slychko
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Jiří Červeň
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Petr Pečinka
- Department of Biology and Ecology, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Donna J Arndt-Jovin
- Emeritus Laboratory of Cellular Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Thomas M Jovin
- Emeritus Laboratory of Cellular Dynamics, Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
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4
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García-Nieto A, Patel A, Li Y, Oldenkamp R, Feletto L, Graham JJ, Willems L, Muir KW, Panne D, Rowland BD. Structural basis of centromeric cohesion protection. Nat Struct Mol Biol 2023:10.1038/s41594-023-00968-y. [PMID: 37081319 DOI: 10.1038/s41594-023-00968-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 03/15/2023] [Indexed: 04/22/2023]
Abstract
In the early stages of mitosis, cohesin is released from chromosome arms but not from centromeres. The protection of centromeric cohesin by SGO1 maintains the sister chromatid cohesion that resists the pulling forces of microtubules until all chromosomes are attached in a bipolar manner to the mitotic spindle. Here we present the X-ray crystal structure of a segment of human SGO1 bound to a conserved surface of the cohesin complex. SGO1 binds to a composite interface formed by the SA2 and SCC1RAD21 subunits of cohesin. SGO1 shares this binding interface with CTCF, indicating that these distinct chromosomal regulators control cohesin through a universal principle. This interaction is essential for the localization of SGO1 to centromeres and protects centromeric cohesin against WAPL-mediated cohesin release. SGO1-cohesin binding is maintained until the formation of microtubule-kinetochore attachments and is required for faithful chromosome segregation and the maintenance of a stable karyotype.
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Affiliation(s)
- Alberto García-Nieto
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Amrita Patel
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Yan Li
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Roel Oldenkamp
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Leonardo Feletto
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Joshua J Graham
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Laureen Willems
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Kyle W Muir
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Daniel Panne
- Leicester Institute of Structural and Chemical Biology, Department of Molecular and Cell Biology, University of Leicester, Leicester, UK.
| | - Benjamin D Rowland
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
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5
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de Wit E, Nora EP. New insights into genome folding by loop extrusion from inducible degron technologies. Nat Rev Genet 2023; 24:73-85. [PMID: 36180596 DOI: 10.1038/s41576-022-00530-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2022] [Indexed: 01/24/2023]
Abstract
Chromatin folds into dynamic loops that often span hundreds of kilobases and physically wire distant loci together for gene regulation. These loops are continuously created, extended and positioned by structural maintenance of chromosomes (SMC) protein complexes, such as condensin and cohesin, and their regulators, including CTCF, in a highly dynamic process known as loop extrusion. Genetic loss of extrusion factors is lethal, complicating their study. Inducible protein degradation technologies enable the depletion of loop extrusion factors within hours, leading to the rapid reconfiguration of chromatin folding. Here, we review how these technologies have changed our understanding of genome organization, upsetting long-held beliefs on its role in transcription. Finally, we examine recent models that attempt to reconcile observations after chronic versus acute perturbations, and discuss future developments in this rapidly developing field of research.
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Affiliation(s)
- Elzo de Wit
- Division of Gene Regulation, Oncode Institute, Amsterdam, the Netherlands.
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Elphège P Nora
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
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6
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Kim JH, Youn Y, Hwang JH. NCAPH Stabilizes GEN1 in Chromatin to Resolve Ultra-Fine DNA Bridges and Maintain Chromosome Stability. Mol Cells 2022; 45:792-805. [PMID: 36380731 PMCID: PMC9676985 DOI: 10.14348/molcells.2022.0048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/11/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Repairing damaged DNA and removing all physical connections between sister chromosomes is important to ensure proper chromosomal segregation by contributing to chromosomal stability. Here, we show that the depletion of non-SMC condensin I complex subunit H (NCAPH) exacerbates chromosome segregation errors and cytokinesis failure owing to sister-chromatid intertwinement, which is distinct from the ultra-fine DNA bridges induced by DNA inter-strand crosslinks (DNA-ICLs). Importantly, we identified an interaction between NCAPH and GEN1 in the chromatin involving binding at the N-terminus of NCAPH. DNA-ICL activation, using ICL-inducing agents, increased the expression and interaction between NCAPH and GEN1 in the soluble nuclear and chromatin, indicating that the NCAPH-GEN1 interaction participates in repairing DNA damage. Moreover, NCAPH stabilizes GEN1 within chromatin at the G2/M-phase and is associated with DNA-ICL-induced damage repair. Therefore, NCAPH resolves DNA-ICL-induced ultra-fine DNA bridges by stabilizing GEN1 and ensures proper chromosome separation and chromosome structural stability.
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Affiliation(s)
- Jae Hyeong Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Yuna Youn
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Jin-Hyeok Hwang
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Korea
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7
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A global high-density chromatin interaction network reveals functional long-range and trans-chromosomal relationships. Genome Biol 2022; 23:238. [PMID: 36352464 PMCID: PMC9647974 DOI: 10.1186/s13059-022-02790-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 10/10/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chromatin contacts are essential for gene-expression regulation; however, obtaining a high-resolution genome-wide chromatin contact map is still prohibitively expensive owing to large genome sizes and the quadratic scale of pairwise data. Chromosome conformation capture (3C)-based methods such as Hi-C have been extensively used to obtain chromatin contacts. However, since the sparsity of these maps increases with an increase in genomic distance between contacts, long-range or trans-chromatin contacts are especially challenging to sample. RESULTS Here, we create a high-density reference genome-wide chromatin contact map using a meta-analytic approach. We integrate 3600 human, 6700 mouse, and 500 fly Hi-C experiments to create species-specific meta-Hi-C chromatin contact maps with 304 billion, 193 billion, and 19 billion contacts in respective species. We validate that meta-Hi-C contact maps are uniquely powered to capture functional chromatin contacts in both cis and trans. We find that while individual dataset Hi-C networks are largely unable to predict any long-range coexpression (median 0.54 AUC), meta-Hi-C networks perform comparably in both cis and trans (0.65 AUC vs 0.64 AUC). Similarly, for long-range expression quantitative trait loci (eQTL), meta-Hi-C contacts outperform all individual Hi-C experiments, providing an improvement over the conventionally used linear genomic distance-based association. Assessing between species, we find patterns of chromatin contact conservation in both cis and trans and strong associations with coexpression even in species for which Hi-C data is lacking. CONCLUSIONS We have generated an integrated chromatin interaction network which complements a large number of methodological and analytic approaches focused on improved specificity or interpretation. This high-depth "super-experiment" is surprisingly powerful in capturing long-range functional relationships of chromatin interactions, which are now able to predict coexpression, eQTLs, and cross-species relationships. The meta-Hi-C networks are available at https://labshare.cshl.edu/shares/gillislab/resource/HiC/ .
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8
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Regulation of the mitotic chromosome folding machines. Biochem J 2022; 479:2153-2173. [PMID: 36268993 DOI: 10.1042/bcj20210140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/17/2022]
Abstract
Over the last several years enormous progress has been made in identifying the molecular machines, including condensins and topoisomerases that fold mitotic chromosomes. The discovery that condensins generate chromatin loops through loop extrusion has revolutionized, and energized, the field of chromosome folding. To understand how these machines fold chromosomes with the appropriate dimensions, while disentangling sister chromatids, it needs to be determined how they are regulated and deployed. Here, we outline the current understanding of how these machines and factors are regulated through cell cycle dependent expression, chromatin localization, activation and inactivation through post-translational modifications, and through associations with each other, with other factors and with the chromatin template itself. There are still many open questions about how condensins and topoisomerases are regulated but given the pace of progress in the chromosome folding field, it seems likely that many of these will be answered in the years ahead.
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9
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van Schaik T, Manzo SG, Vouzas AE, Liu NQ, Teunissen H, de Wit E, Gilbert DM, van Steensel B. Dynamic chromosomal interactions and control of heterochromatin positioning by Ki-67. EMBO Rep 2022; 23:e55782. [PMID: 36245428 PMCID: PMC9724667 DOI: 10.15252/embr.202255782] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022] Open
Abstract
Ki-67 is a chromatin-associated protein with a dynamic distribution pattern throughout the cell cycle and is thought to be involved in chromatin organization. The lack of genomic interaction maps has hampered a detailed understanding of its roles, particularly during interphase. By pA-DamID mapping in human cell lines, we find that Ki-67 associates with large genomic domains that overlap mostly with late-replicating regions. Early in interphase, when Ki-67 is present in pre-nucleolar bodies, it interacts with these domains on all chromosomes. However, later in interphase, when Ki-67 is confined to nucleoli, it shows a striking shift toward small chromosomes. Nucleolar perturbations indicate that these cell cycle dynamics correspond to nucleolar maturation during interphase, and suggest that nucleolar sequestration of Ki-67 limits its interactions with larger chromosomes. Furthermore, we demonstrate that Ki-67 does not detectably control chromatin-chromatin interactions during interphase, but it competes with the nuclear lamina for interaction with late-replicating DNA, and it controls replication timing of (peri)centromeric regions. Together, these results reveal a highly dynamic choreography of genome interactions and roles for Ki-67 in heterochromatin organization.
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Affiliation(s)
- Tom van Schaik
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Stefano G Manzo
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Athanasios E Vouzas
- Department of Biological ScienceThe Florida State UniversityTallahasseeFLUSA,San Diego Biomedical Research InstituteSan DiegoCAUSA
| | - Ning Qing Liu
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Hans Teunissen
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Elzo de Wit
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - David M Gilbert
- Department of Biological ScienceThe Florida State UniversityTallahasseeFLUSA,San Diego Biomedical Research InstituteSan DiegoCAUSA
| | - Bas van Steensel
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands,Department of Cell BiologyErasmus University Medical CentreRotterdamThe Netherlands
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10
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Macdonald L, Taylor GC, Brisbane JM, Christodoulou E, Scott L, von Kriegsheim A, Rossant J, Gu B, Wood AJ. Rapid and specific degradation of endogenous proteins in mouse models using auxin-inducible degrons. eLife 2022; 11:e77987. [PMID: 35736539 PMCID: PMC9273210 DOI: 10.7554/elife.77987] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/19/2022] [Indexed: 11/13/2022] Open
Abstract
Auxin-inducible degrons are a chemical genetic tool for targeted protein degradation and are widely used to study protein function in cultured mammalian cells. Here, we develop CRISPR-engineered mouse lines that enable rapid and highly specific degradation of tagged endogenous proteins in vivo. Most but not all cell types are competent for degradation. By combining ligand titrations with genetic crosses to generate animals with different allelic combinations, we show that degradation kinetics depend upon the dose of the tagged protein, ligand, and the E3 ligase substrate receptor TIR1. Rapid degradation of condensin I and II - two essential regulators of mitotic chromosome structure - revealed that both complexes are individually required for cell division in precursor lymphocytes, but not in their differentiated peripheral lymphocyte derivatives. This generalisable approach provides unprecedented temporal control over the dose of endogenous proteins in mouse models, with implications for studying essential biological pathways and modelling drug activity in mammalian tissues.
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Affiliation(s)
- Lewis Macdonald
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Gillian C Taylor
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Jennifer Margaret Brisbane
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Ersi Christodoulou
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Lucy Scott
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Alex von Kriegsheim
- Cancer Research UK Edinburgh Centre, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
| | - Janet Rossant
- Program in Developmental and Stem Cell Biology, Hospital for Sick ChildrenTorontoCanada
| | - Bin Gu
- Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State UniversityEast LansingUnited States
- Department of Biomedical Engineering; Michigan State UniversityEast LansingUnited States
- Institute for Quantitative Health Science and Engineering, Michigan State UniversityEast LansingUnited States
| | - Andrew J Wood
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of EdinburghEdinburghUnited Kingdom
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11
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CCAR2 controls mitotic progression through spatiotemporal regulation of Aurora B. Cell Death Dis 2022; 13:534. [PMID: 35672287 PMCID: PMC9174277 DOI: 10.1038/s41419-022-04990-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 01/21/2023]
Abstract
CCAR2 (cell cycle and apoptosis regulator 2) is a multifaceted protein involved in cell survival and death following cytotoxic stress. However, little is known about the physiological functions of CCAR2 in regulating cell proliferation in the absence of external stimuli. The present study shows that CCAR2-deficient cells possess multilobulated nuclei, suggesting a defect in cell division. In particular, the duration of mitotic phase was perturbed. This disturbance of mitotic progression resulted from premature loss of cohesion with the centromere, and inactivation of the spindle assembly checkpoint during prometaphase and metaphase. It resulted in the formation of lagging chromosomes during anaphase, leading ultimately to the activation of the abscission checkpoint to halt cytokinesis. The CCAR2-dependent mitotic progression was related to spatiotemporal regulation of active Aurora B. In conclusion, the results suggest that CCAR2 governs mitotic events, including proper chromosome segregation and cytokinetic division, to maintain chromosomal stability.
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12
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A walk through the SMC cycle: From catching DNAs to shaping the genome. Mol Cell 2022; 82:1616-1630. [PMID: 35477004 DOI: 10.1016/j.molcel.2022.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 02/02/2022] [Accepted: 04/04/2022] [Indexed: 12/16/2022]
Abstract
SMC protein complexes are molecular machines that provide structure to chromosomes. These complexes bridge DNA elements and by doing so build DNA loops in cis and hold together the sister chromatids in trans. We discuss how drastic conformational changes allow SMC complexes to build such intricate DNA structures. The tight regulation of these complexes controls fundamental chromosomal processes such as transcription, recombination, repair, and mitosis.
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13
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Haase J, Chen R, Parker WM, Bonner MK, Jenkins LM, Kelly AE. The TFIIH complex is required to establish and maintain mitotic chromosome structure. eLife 2022; 11:75475. [PMID: 35293859 PMCID: PMC8956287 DOI: 10.7554/elife.75475] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Condensins compact chromosomes to promote their equal segregation during mitosis, but the mechanism of condensin engagement with and action on chromatin is incompletely understood. Here, we show that the general transcription factor TFIIH complex is continuously required to establish and maintain a compacted chromosome structure in transcriptionally silent Xenopus egg extracts. Inhibiting the DNA-dependent ATPase activity of the TFIIH complex subunit XPB rapidly and reversibly induces a complete loss of chromosome structure and prevents the enrichment of condensins I and II, but not topoisomerase II, on chromatin. In addition, inhibiting TFIIH prevents condensation of both mouse and Xenopus nuclei in Xenopus egg extracts, which suggests an evolutionarily conserved mechanism of TFIIH action. Reducing nucleosome density through partial histone depletion restores chromosome structure and condensin enrichment in the absence of TFIIH activity. We propose that the TFIIH complex promotes mitotic chromosome condensation by dynamically altering the chromatin environment to facilitate condensin loading and condensin-dependent loop extrusion.
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Affiliation(s)
- Julian Haase
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Richard Chen
- Graduate School of Biomedical Sciences, The University of Texas Southwestern Medical Center, Dallas, United States
| | - Wesley M Parker
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Mary Kate Bonner
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Lisa M Jenkins
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
| | - Alexander E Kelly
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, United States
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14
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Abstract
The centromere serves as the binding site for the kinetochore and is essential for the faithful segregation of chromosomes throughout cell division. The point centromere in yeast is encoded by a ∼115 bp specific DNA sequence, whereas regional centromeres range from 6-10 kbp in fission yeast to 5-10 Mbp in humans. Understanding the physical structure of centromere chromatin (pericentromere in yeast), defined as the chromatin between sister kinetochores, will provide fundamental insights into how centromere DNA is woven into a stiff spring that is able to resist microtubule pulling forces during mitosis. One hallmark of the pericentromere is the enrichment of the structural maintenance of chromosome (SMC) proteins cohesin and condensin. Based on studies from population approaches (ChIP-seq and Hi-C) and experimentally obtained images of fluorescent probes of pericentromeric structure, as well as quantitative comparisons between simulations and experimental results, we suggest a mechanism for building tension between sister kinetochores. We propose that the centromere is a chromatin bottlebrush that is organized by the loop-extruding proteins condensin and cohesin. The bottlebrush arrangement provides a biophysical means to transform pericentromeric chromatin into a spring due to the steric repulsion between radial loops. We argue that the bottlebrush is an organizing principle for chromosome organization that has emerged from multiple approaches in the field.
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15
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Chanboonyasitt P, Chan YW. Regulation of mitotic chromosome architecture and resolution of ultrafine anaphase bridges by PICH. Cell Cycle 2021; 20:2077-2090. [PMID: 34530686 PMCID: PMC8565832 DOI: 10.1080/15384101.2021.1970877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/28/2021] [Accepted: 08/16/2021] [Indexed: 11/30/2022] Open
Abstract
To ensure genome stability, chromosomes need to undergo proper condensation into two linked sister chromatids from prophase to prometaphase, followed by equal segregation at anaphase. Emerging evidence has shown that persistent DNA entanglements connecting the sister chromatids lead to the formation of ultrafine anaphase bridges (UFBs). If UFBs are not resolved soon after anaphase, they can induce chromosome missegregation. PICH (PLK1-interacting checkpoint helicase) is a DNA translocase that localizes on chromosome arms, centromeres and UFBs. It plays multiple essential roles in mitotic chromosome organization and segregation. PICH also recruits other associated proteins to UFBs, and together they mediate UFB resolution. Here, the proposed mechanism behind PICH's functions in chromosome organization and UFB resolution will be discussed. We summarize the regulation of PICH action at chromosome arms and centromeres, how PICH recognizes UFBs and recruits other UFB-associated factors, and finally how PICH promotes UFB resolution together with other DNA processing enzymes.
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Affiliation(s)
| | - Ying Wai Chan
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
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16
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Choppakatla P, Dekker B, Cutts EE, Vannini A, Dekker J, Funabiki H. Linker histone H1.8 inhibits chromatin binding of condensins and DNA topoisomerase II to tune chromosome length and individualization. eLife 2021; 10:e68918. [PMID: 34406118 PMCID: PMC8416026 DOI: 10.7554/elife.68918] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/13/2021] [Indexed: 12/14/2022] Open
Abstract
DNA loop extrusion by condensins and decatenation by DNA topoisomerase II (topo II) are thought to drive mitotic chromosome compaction and individualization. Here, we reveal that the linker histone H1.8 antagonizes condensins and topo II to shape mitotic chromosome organization. In vitro chromatin reconstitution experiments demonstrate that H1.8 inhibits binding of condensins and topo II to nucleosome arrays. Accordingly, H1.8 depletion in Xenopus egg extracts increased condensins and topo II levels on mitotic chromatin. Chromosome morphology and Hi-C analyses suggest that H1.8 depletion makes chromosomes thinner and longer through shortening the average loop size and reducing the DNA amount in each layer of mitotic loops. Furthermore, excess loading of condensins and topo II to chromosomes by H1.8 depletion causes hyper-chromosome individualization and dispersion. We propose that condensins and topo II are essential for chromosome individualization, but their functions are tuned by the linker histone to keep chromosomes together until anaphase.
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Affiliation(s)
- Pavan Choppakatla
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
| | - Bastiaan Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Erin E Cutts
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer ResearchLondonUnited Kingdom
- Fondazione Human Technopole, Structural Biology Research Centre, 20157MilanItaly
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Hironori Funabiki
- Laboratory of Chromosome and Cell Biology, The Rockefeller UniversityNew YorkUnited States
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17
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Davidson IF, Peters JM. Genome folding through loop extrusion by SMC complexes. Nat Rev Mol Cell Biol 2021; 22:445-464. [PMID: 33767413 DOI: 10.1038/s41580-021-00349-7] [Citation(s) in RCA: 206] [Impact Index Per Article: 68.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2021] [Indexed: 02/02/2023]
Abstract
Genomic DNA is folded into loops and topologically associating domains (TADs), which serve important structural and regulatory roles. It has been proposed that these genomic structures are formed by a loop extrusion process, which is mediated by structural maintenance of chromosomes (SMC) protein complexes. Recent single-molecule studies have shown that the SMC complexes condensin and cohesin are indeed able to extrude DNA into loops. In this Review, we discuss how the loop extrusion hypothesis can explain key features of genome architecture; cellular functions of loop extrusion, such as separation of replicated DNA molecules, facilitation of enhancer-promoter interactions and immunoglobulin gene recombination; and what is known about the mechanism of loop extrusion and its regulation, for example, by chromatin boundaries that depend on the DNA binding protein CTCF. We also discuss how the loop extrusion hypothesis has led to a paradigm shift in our understanding of both genome architecture and the functions of SMC complexes.
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Affiliation(s)
- Iain F Davidson
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Jan-Michael Peters
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria.
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18
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Hallett ST, Schellenberger P, Zhou L, Beuron F, Morris E, Murray JM, Oliver AW. Nse5/6 is a negative regulator of the ATPase activity of the Smc5/6 complex. Nucleic Acids Res 2021; 49:4534-4549. [PMID: 33849072 PMCID: PMC8096239 DOI: 10.1093/nar/gkab234] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/18/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
The multi-component Smc5/6 complex plays a critical role in the resolution of recombination intermediates formed during mitosis and meiosis, and in the cellular response to replication stress. Using recombinant proteins, we have reconstituted a series of defined Saccharomyces cerevisiae Smc5/6 complexes, visualised them by negative stain electron microscopy, and tested their ability to function as an ATPase. We find that only the six protein ‘holo-complex’ is capable of turning over ATP and that its activity is significantly increased by the addition of double-stranded DNA to reaction mixes. Furthermore, stimulation is wholly dependent on functional ATP-binding pockets in both Smc5 and Smc6. Importantly, we demonstrate that budding yeast Nse5/6 acts as a negative regulator of Smc5/6 ATPase activity, binding to the head-end of the complex to suppress turnover, irrespective of the DNA-bound status of the complex.
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Affiliation(s)
- Stephen T Hallett
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, UK
| | - Pascale Schellenberger
- Electron Microscopy Imaging Centre, School of Life Sciences, University of Sussex, Falmer, UK
| | - Lihong Zhou
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, UK
| | | | - Ed Morris
- The Institute of Cancer Research, London, UK
| | - Johanne M Murray
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, UK
| | - Antony W Oliver
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, UK
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19
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Relating SMCHD1 structure to its function in epigenetic silencing. Biochem Soc Trans 2021; 48:1751-1763. [PMID: 32779700 PMCID: PMC7458401 DOI: 10.1042/bst20200242] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023]
Abstract
The structural maintenance of chromosomes hinge domain containing protein 1 (SMCHD1) is a large multidomain protein involved in epigenetic gene silencing. Variations in the SMCHD1 gene are associated with two debilitating human disorders, facioscapulohumeral muscular dystrophy (FSHD) and Bosma arhinia microphthalmia syndrome (BAMS). Failure of SMCHD1 to silence the D4Z4 macro-repeat array causes FSHD, yet the consequences on gene silencing of SMCHD1 variations associated with BAMS are currently unknown. Despite the interest due to these roles, our understanding of the SMCHD1 protein is in its infancy. Most knowledge of SMCHD1 function is based on its similarity to the structural maintenance of chromosomes (SMC) proteins, such as cohesin and condensin. SMC proteins and SMCHD1 share similar domain organisation and affect chromatin conformation. However, there are important differences between the domain architectures of SMC proteins and SMCHD1, which distinguish SMCHD1 as a non-canonical member of the family. In the last year, the crystal structures of the two key domains crucial to SMCHD1 function, the ATPase and hinge domains, have emerged. These structures reveal new insights into how SMCHD1 may bind and regulate chromatin structure, and address how amino acid variations in SMCHD1 may contribute to BAMS and FSHD. Here, we contrast SMCHD1 with canonical SMC proteins, and relate the ATPase and hinge domain structures to their roles in SMCHD1-mediated epigenetic silencing and disease.
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20
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Hoencamp C, Dudchenko O, Elbatsh AMO, Brahmachari S, Raaijmakers JA, van Schaik T, Sedeño Cacciatore Á, Contessoto VG, van Heesbeen RGHP, van den Broek B, Mhaskar AN, Teunissen H, St Hilaire BG, Weisz D, Omer AD, Pham M, Colaric Z, Yang Z, Rao SSP, Mitra N, Lui C, Yao W, Khan R, Moroz LL, Kohn A, St Leger J, Mena A, Holcroft K, Gambetta MC, Lim F, Farley E, Stein N, Haddad A, Chauss D, Mutlu AS, Wang MC, Young ND, Hildebrandt E, Cheng HH, Knight CJ, Burnham TLU, Hovel KA, Beel AJ, Mattei PJ, Kornberg RD, Warren WC, Cary G, Gómez-Skarmeta JL, Hinman V, Lindblad-Toh K, Di Palma F, Maeshima K, Multani AS, Pathak S, Nel-Themaat L, Behringer RR, Kaur P, Medema RH, van Steensel B, de Wit E, Onuchic JN, Di Pierro M, Lieberman Aiden E, Rowland BD. 3D genomics across the tree of life reveals condensin II as a determinant of architecture type. Science 2021; 372:984-989. [PMID: 34045355 PMCID: PMC8172041 DOI: 10.1126/science.abe2218] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/16/2021] [Indexed: 01/01/2023]
Abstract
We investigated genome folding across the eukaryotic tree of life. We find two types of three-dimensional (3D) genome architectures at the chromosome scale. Each type appears and disappears repeatedly during eukaryotic evolution. The type of genome architecture that an organism exhibits correlates with the absence of condensin II subunits. Moreover, condensin II depletion converts the architecture of the human genome to a state resembling that seen in organisms such as fungi or mosquitoes. In this state, centromeres cluster together at nucleoli, and heterochromatin domains merge. We propose a physical model in which lengthwise compaction of chromosomes by condensin II during mitosis determines chromosome-scale genome architecture, with effects that are retained during the subsequent interphase. This mechanism likely has been conserved since the last common ancestor of all eukaryotes.
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Affiliation(s)
- Claire Hoencamp
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Olga Dudchenko
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - Ahmed M O Elbatsh
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | | | - Jonne A Raaijmakers
- Division of Cell Biology, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Tom van Schaik
- Division of Gene Regulation, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | | | - Vinícius G Contessoto
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
- Department of Physics, Institute of Biosciences, Letters and Exact Sciences, São Paulo State University (UNESP), São José do Rio Preto - SP, 15054-000, Brazil
| | - Roy G H P van Heesbeen
- Division of Cell Biology, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Bram van den Broek
- BioImaging Facility, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Aditya N Mhaskar
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Hans Teunissen
- Division of Gene Regulation, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Brian Glenn St Hilaire
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - David Weisz
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Arina D Omer
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Melanie Pham
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zane Colaric
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhenzhen Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech, Pudong 201210, China
| | - Suhas S P Rao
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Namita Mitra
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christopher Lui
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Weijie Yao
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ruqayya Khan
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Leonid L Moroz
- Whitney Laboratory and Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA
| | - Andrea Kohn
- Whitney Laboratory and Department of Neuroscience, University of Florida, Gainesville, FL 32611, USA
| | - Judy St Leger
- Department of Biosciences, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | | | | | | | - Fabian Lim
- Department of Medicine and Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emma Farley
- Department of Medicine and Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nils Stein
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK Gatersleben), 06466 Seeland, Germany
- Center of Integrated Breeding Research (CiBreed), Department of Crop Sciences, Georg-August-University Göttingen, 37075 Göttingen, Germany
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia
| | - Alexander Haddad
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniel Chauss
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ayse Sena Mutlu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng C Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Neil D Young
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Evin Hildebrandt
- Avian Diseases and Oncology Laboratory, US Department of Agriculture, Agricultural Research Service, East Lansing, MI 48823, USA
| | - Hans H Cheng
- Avian Diseases and Oncology Laboratory, US Department of Agriculture, Agricultural Research Service, East Lansing, MI 48823, USA
| | | | - Theresa L U Burnham
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA 95616, USA
- Coastal and Marine Institute and Department of Biology, San Diego State University, San Diego, CA 92106, USA
| | - Kevin A Hovel
- Coastal and Marine Institute and Department of Biology, San Diego State University, San Diego, CA 92106, USA
| | - Andrew J Beel
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Pierre-Jean Mattei
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Roger D Kornberg
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wesley C Warren
- Department of Animal Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Gregory Cary
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - José Luis Gómez-Skarmeta
- Centro Andaluz de Biología del Desarrollo CSIC, Universidad Pablo de Olavide, 41013 Sevilla, Spain
| | - Veronica Hinman
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Kerstin Lindblad-Toh
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, 751 23 Uppsala, Sweden
| | - Federica Di Palma
- Department of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
- Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka 411-8540, Japan
| | - Asha S Multani
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sen Pathak
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Liesl Nel-Themaat
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Richard R Behringer
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Parwinder Kaur
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia
| | - René H Medema
- Division of Cell Biology, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - Elzo de Wit
- Division of Gene Regulation, Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
- Departments of Physics and Astronomy, Chemistry, and Biosciences, Rice University, Houston, TX 77005, USA
| | - Michele Di Pierro
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech, Pudong 201210, China
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6009, Australia
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Benjamin D Rowland
- Division of Gene Regulation, Netherlands Cancer Institute, 1066 CX Amsterdam, Netherlands.
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21
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Municio C, Antosz W, Grasser KD, Kornobis E, Van Bel M, Eguinoa I, Coppens F, Bräutigam A, Lermontova I, Bruckmann A, Zelkowska K, Houben A, Schubert V. The Arabidopsis condensin CAP-D subunits arrange interphase chromatin. THE NEW PHYTOLOGIST 2021; 230:972-987. [PMID: 33475158 DOI: 10.1111/nph.17221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Condensins are best known for their role in shaping chromosomes. Other functions such as organizing interphase chromatin and transcriptional control have been reported in yeasts and animals, but little is known about their function in plants. To elucidate the specific composition of condensin complexes and the expression of CAP-D2 (condensin I) and CAP-D3 (condensin II), we performed biochemical analyses in Arabidopsis. The role of CAP-D3 in interphase chromatin organization and function was evaluated using cytogenetic and transcriptome analysis in cap-d3 T-DNA insertion mutants. CAP-D2 and CAP-D3 are highly expressed in mitotically active tissues. In silico and pull-down experiments indicate that both CAP-D proteins interact with the other condensin I and II subunits. In cap-d3 mutants, an association of heterochromatic sequences occurs, but the nuclear size and the general histone and DNA methylation patterns remain unchanged. Also, CAP-D3 influences the expression of genes affecting the response to water, chemicals, and stress. The expression and composition of the condensin complexes in Arabidopsis are similar to those in other higher eukaryotes. We propose a model for the CAP-D3 function during interphase in which CAP-D3 localizes in euchromatin loops to stiffen them and consequently separates centromeric regions and 45S rDNA repeats.
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Affiliation(s)
- Celia Municio
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, D-06466, Seeland, Germany
| | - Wojciech Antosz
- Cell Biology and Plant Biochemistry, Biochemistry Center, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Klaus D Grasser
- Cell Biology and Plant Biochemistry, Biochemistry Center, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Etienne Kornobis
- Plate-forme Technologique Biomics - Centre de Ressources et Recherches Technologiques (C2RT), Institut Pasteur, 75015, Paris, France
- Hub de Bioinformatique et Biostatistique -Département Biologie Computationnelle, Institut Pasteur, 75015, Paris, France
| | - Michiel Van Bel
- VIB-UGent Center for Plant Systems Biology, Technologiepark 71, 9052, Gent, Belgium
| | - Ignacio Eguinoa
- VIB-UGent Center for Plant Systems Biology, Technologiepark 71, 9052, Gent, Belgium
| | - Frederik Coppens
- VIB-UGent Center for Plant Systems Biology, Technologiepark 71, 9052, Gent, Belgium
| | - Andrea Bräutigam
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, D-06466, Seeland, Germany
| | - Inna Lermontova
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, D-06466, Seeland, Germany
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Brno, CZ-62500, Czech Republic
| | - Astrid Bruckmann
- Department for Biochemistry I, Biochemistry Center, University of Regensburg, Universitätsstraße 31, D-93053, Regensburg, Germany
| | - Katarzyna Zelkowska
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, D-06466, Seeland, Germany
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, D-06466, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, D-06466, Seeland, Germany
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22
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Etheridge TJ, Villahermosa D, Campillo-Funollet E, Herbert AD, Irmisch A, Watson AT, Dang HQ, Osborne MA, Oliver AW, Carr AM, Murray JM. Live-cell single-molecule tracking highlights requirements for stable Smc5/6 chromatin association in vivo. eLife 2021; 10:e68579. [PMID: 33860765 PMCID: PMC8075580 DOI: 10.7554/elife.68579] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 04/15/2021] [Indexed: 12/17/2022] Open
Abstract
The essential Smc5/6 complex is required in response to replication stress and is best known for ensuring the fidelity of homologous recombination. Using single-molecule tracking in live fission yeast to investigate Smc5/6 chromatin association, we show that Smc5/6 is chromatin associated in unchallenged cells and this depends on the non-SMC protein Nse6. We define a minimum of two Nse6-dependent sub-pathways, one of which requires the BRCT-domain protein Brc1. Using defined mutants in genes encoding the core Smc5/6 complex subunits, we show that the Nse3 double-stranded DNA binding activity and the arginine fingers of the two Smc5/6 ATPase binding sites are critical for chromatin association. Interestingly, disrupting the single-stranded DNA (ssDNA) binding activity at the hinge region does not prevent chromatin association but leads to elevated levels of gross chromosomal rearrangements during replication restart. This is consistent with a downstream function for ssDNA binding in regulating homologous recombination.
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Affiliation(s)
- Thomas J Etheridge
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Desiree Villahermosa
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Eduard Campillo-Funollet
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Alex David Herbert
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Anja Irmisch
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Adam T Watson
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Hung Q Dang
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Mark A Osborne
- Chemistry Department, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Antony W Oliver
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Johanne M Murray
- Genome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
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23
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Paulson JR, Hudson DF, Cisneros-Soberanis F, Earnshaw WC. Mitotic chromosomes. Semin Cell Dev Biol 2021; 117:7-29. [PMID: 33836947 PMCID: PMC8406421 DOI: 10.1016/j.semcdb.2021.03.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/23/2021] [Accepted: 03/23/2021] [Indexed: 01/25/2023]
Abstract
Our understanding of the structure and function of mitotic chromosomes has come a long way since these iconic objects were first recognized more than 140 years ago, though many details remain to be elucidated. In this chapter, we start with the early history of chromosome studies and then describe the path that led to our current understanding of the formation and structure of mitotic chromosomes. We also discuss some of the remaining questions. It is now well established that each mitotic chromatid consists of a central organizing region containing a so-called "chromosome scaffold" from which loops of DNA project radially. Only a few key non-histone proteins and protein complexes are required to form the chromosome: topoisomerase IIα, cohesin, condensin I and condensin II, and the chromokinesin KIF4A. These proteins are concentrated along the axis of the chromatid. Condensins I and II are primarily responsible for shaping the chromosome and the scaffold, and they produce the loops of DNA by an ATP-dependent process known as loop extrusion. Modelling of Hi-C data suggests that condensin II adopts a spiral staircase arrangement with an extruded loop extending out from each step in a roughly helical pattern. Condensin I then forms loops nested within these larger condensin II loops, thereby giving rise to the final compaction of the mitotic chromosome in a process that requires Topo IIα.
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Affiliation(s)
- James R Paulson
- Department of Chemistry, University of Wisconsin Oshkosh, 800 Algoma Boulevard, Oshkosh, WI 54901, USA.
| | - Damien F Hudson
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia
| | - Fernanda Cisneros-Soberanis
- Wellcome Trust Centre for Cell Biology, ICB, University of Edinburgh, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, ICB, University of Edinburgh, Michael Swann Building, King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, Scotland, UK.
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Matityahu A, Onn I. Hit the brakes - a new perspective on the loop extrusion mechanism of cohesin and other SMC complexes. J Cell Sci 2021; 134:jcs247577. [PMID: 33419949 DOI: 10.1242/jcs.247577] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The three-dimensional structure of chromatin is determined by the action of protein complexes of the structural maintenance of chromosome (SMC) family. Eukaryotic cells contain three SMC complexes, cohesin, condensin, and a complex of Smc5 and Smc6. Initially, cohesin was linked to sister chromatid cohesion, the process that ensures the fidelity of chromosome segregation in mitosis. In recent years, a second function in the organization of interphase chromatin into topologically associated domains has been determined, and loop extrusion has emerged as the leading mechanism of this process. Interestingly, fundamental mechanistic differences exist between mitotic tethering and loop extrusion. As distinct molecular switches that aim to suppress loop extrusion in different biological contexts have been identified, we hypothesize here that loop extrusion is the default biochemical activity of cohesin and that its suppression shifts cohesin into a tethering mode. With this model, we aim to provide an explanation for how loop extrusion and tethering can coexist in a single cohesin complex and also apply it to the other eukaryotic SMC complexes, describing both similarities and differences between them. Finally, we present model-derived molecular predictions that can be tested experimentally, thus offering a new perspective on the mechanisms by which SMC complexes shape the higher-order structure of chromatin.
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Affiliation(s)
- Avi Matityahu
- 8 Henrietta Szold St., The Azrieli Faculty of Medicine, Bar-Ilan University, P.O. Box 1589 Safed, Israel
| | - Itay Onn
- 8 Henrietta Szold St., The Azrieli Faculty of Medicine, Bar-Ilan University, P.O. Box 1589 Safed, Israel
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25
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Cutts EE, Vannini A. Condensin complexes: understanding loop extrusion one conformational change at a time. Biochem Soc Trans 2020; 48:2089-2100. [PMID: 33005926 PMCID: PMC7609036 DOI: 10.1042/bst20200241] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022]
Abstract
Condensin and cohesin, both members of the structural maintenance of chromosome (SMC) family, contribute to the regulation and structure of chromatin. Recent work has shown both condensin and cohesin extrude DNA loops and most likely work via a conserved mechanism. This review focuses on condensin complexes, highlighting recent in vitro work characterising DNA loop formation and protein structure. We discuss similarities between condensin and cohesin complexes to derive a possible mechanistic model, as well as discuss differences that exist between the different condensin isoforms found in higher eukaryotes.
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Affiliation(s)
- Erin E. Cutts
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, U.K
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer Research, London SW7 3RP, U.K
- Fondazione Human Technopole, Structural Biology Research Centre, 20157 Milan, Italy
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26
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Loop extrusion: theory meets single-molecule experiments. Curr Opin Cell Biol 2020; 64:124-138. [PMID: 32534241 DOI: 10.1016/j.ceb.2020.04.011] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/24/2020] [Accepted: 04/28/2020] [Indexed: 11/20/2022]
Abstract
Chromosomes are organized as chromatin loops that promote segregation, enhancer-promoter interactions, and other genomic functions. Loops were hypothesized to form by 'loop extrusion,' by which structural maintenance of chromosomes (SMC) complexes, such as condensin and cohesin, bind to chromatin, reel it in, and extrude it as a loop. However, such exotic motor activity had never been observed. Following an explosion of indirect evidence, recent single-molecule experiments directly imaged DNA loop extrusion by condensin and cohesin in vitro. These experiments observe rapid (kb/s) extrusion that requires ATP hydrolysis and stalls under pN forces. Surprisingly, condensin extrudes loops asymmetrically, challenging previous models. Extrusion by cohesin is symmetric but requires the protein Nipbl. We discuss how SMC complexes may perform their functions on chromatin in vivo.
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27
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Banigan EJ, van den Berg AA, Brandão HB, Marko JF, Mirny LA. Chromosome organization by one-sided and two-sided loop extrusion. eLife 2020; 9:e53558. [PMID: 32250245 PMCID: PMC7295573 DOI: 10.7554/elife.53558] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 04/03/2020] [Indexed: 12/19/2022] Open
Abstract
SMC complexes, such as condensin or cohesin, organize chromatin throughout the cell cycle by a process known as loop extrusion. SMC complexes reel in DNA, extruding and progressively growing DNA loops. Modeling assuming two-sided loop extrusion reproduces key features of chromatin organization across different organisms. In vitro single-molecule experiments confirmed that yeast condensins extrude loops, however, they remain anchored to their loading sites and extrude loops in a 'one-sided' manner. We therefore simulate one-sided loop extrusion to investigate whether 'one-sided' complexes can compact mitotic chromosomes, organize interphase domains, and juxtapose bacterial chromosomal arms, as can be done by 'two-sided' loop extruders. While one-sided loop extrusion cannot reproduce these phenomena, variants can recapitulate in vivo observations. We predict that SMC complexes in vivo constitute effectively two-sided motors or exhibit biased loading and propose relevant experiments. Our work suggests that loop extrusion is a viable general mechanism of chromatin organization.
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Affiliation(s)
- Edward J Banigan
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Aafke A van den Berg
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Hugo B Brandão
- Harvard Graduate Program in Biophysics, Harvard UniversityCambridgeUnited States
| | - John F Marko
- Departments of Molecular Biosciences and Physics & Astronomy, Northwestern UniversityEvanstonUnited States
| | - Leonid A Mirny
- Institute for Medical Engineering & Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Physics, Massachusetts Institute of TechnologyCambridgeUnited States
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28
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Zhou CY, Heald R. Emergent properties of mitotic chromosomes. Curr Opin Cell Biol 2020; 64:43-49. [PMID: 32151949 DOI: 10.1016/j.ceb.2020.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/21/2020] [Accepted: 02/01/2020] [Indexed: 12/27/2022]
Abstract
As a cell prepares to divide, its genetic material changes dramatically in both form and function. During interphase, a dynamic interplay between DNA compartmentalization and transcription functions to program cell identity. During mitosis, this purpose is put on hold and instead chromosomes function to facilitate their accurate segregation to daughter cells. Chromatin loops are rearranged, stacked, and compressed to form X-shaped chromosomes that are neatly aligned at the center of the mitotic spindle and ready to withstand the forces of anaphase. Many factors that contribute to mitotic chromosome assembly have now been identified, but how the plethora of molecular mechanisms operate in concert to give rise to the distinct form and physical properties of mitotic chromosomes at the cellular scale remains under active investigation. In this review, we discuss recent work that addresses a major challenge for the field: How to connect the molecular-level activities to large-scale changes in whole-chromosome architecture that determine mitotic chromosome size, shape, and function.
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Affiliation(s)
- Coral Y Zhou
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720 USA.
| | - Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720 USA.
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